I was knitting a skirt, and when I got to the bottom, I ran across this instruction: "Dec at beg of next 2 rows: 2 sts, then 3 sts, then 4 sts, then 6 sts, then BO all stitches."

The way it looks to me, it's trying to tell me to decrease over the course of 4 rows, but I feel like if that were the case, the pattern would tell me so. If it's just 2 rows, is it asking me to decrease a total of 5 stitches on the 1st row, then a total of ten on the 2nd?
For reference, the pattern I'm having trouble with is called "violet heather," from a book called "The Yarn Garden" by J. Marsha Michler (just in case that helps).

I'm new to knitting, so if anyone could give me a breakdown of how these final few rows are supposed to go, I would greatly appreciate it. Thank you!

Sounds like a european pattern where 'decrease' actually means BO.
So BO 2 sts at the beg of the next 2 rows, 3 sts on the following 2 rows, 4 sts on the next 2 rows, 6 sts after that, then BO all the rest. This will give a slant to the edges.